Which are redox reactions?

I.     \({\text{2FeC}}{{\text{l}}_2} + {\text{C}}{{\text{l}}_2} \to 2{\text{FeC}}{{\text{l}}_{\text{3}}}\)

II.     \({\text{Mg}} + {\text{2HN}}{{\text{O}}_3} \to {\text{Mg(N}}{{\text{O}}_3}{)_2} + {{\text{H}}_2}\)

III.     \({{\text{H}}_2}{\text{O}} + {\text{S}}{{\text{O}}_3} \to {{\text{H}}_2}{\text{S}}{{\text{O}}_4}\)

A.     I and II only

B.     I and III only

C.     II and III only

D.     I, II and III

A